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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:2
UID:UW-Physics-Event-9228
DTSTART:20260227T213000Z
DTEND:20260227T223000Z
DTSTAMP:20260413T085229Z
LAST-MODIFIED:20260122T152913Z
LOCATION:Chamberlin 2241
SUMMARY:Materials that exceed classical thermodynamic bounds on proper
 ties\, Physics Department Colloquium\, Roderic Lakes\, University of W
 isconsin-Madison
DESCRIPTION:Bounds on properties are useful in guiding design of heter
 ogeneous materials and in understanding the distinction between effect
 s that are physically reasonable and those that are not. Several bound
 s on physical properties can be exceeded by an appropriate choice of m
 aterial. The reason is that the “proofs” of bounds contain either 
 unstated assumptions about the material or assumptions that are couche
 d in language that appears to be that of incontrovertible mathematics 
 but that actually entails assumptions about the material. If those ass
 umptions are relaxed\, limits or bounds can be exceeded\, as is demons
 trated by analysis and experiments. For example\, heat capacity\, comp
 ressibility\, electrical capacitance\, and refractive index can be neg
 ative. Thermal expansion in composites can be larger or smaller than t
 hat of any constituent and can be negative. Materials and systems are 
 known that are non-Hermitian or nonreciprocal. Currently\, active fiel
 ds of endeavor have arisen from such conceptual sources. Research effo
 rts have led to the development of new materials and new classes of ma
 terials.
URL:https://www.physics.wisc.edu/events/?id=9228
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